Cementitious composite constituent relationships

ABSTRACT

A cementitious composite for in-situ hydration includes a first layer, a second layer spaced from the first layer, and a cementitious mixture disposed between the first layer and the second layer. The cementitious mixture includes cementitious materials. The cementitious mixture is configured to absorb a mass of water that provides a maximum 28 day compressive strength of the cementitious composite upon curing which is represented by M w =x·M c . M w  is the mass of the water per unit area of the cementitious composite. M c  is a mass of the cementitious materials of the cementitious mixture per unit area of the cementitious composite. x is a ratio of the mass of the water relative to the mass of the cementitious materials of the cementitious mixture per unit area of the cementitious composite that provides the maximum 28 day compressive strength of the cementitious composite. x is between 0.25 and 0.55.

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

This application is related to U.S. patent application Ser. No.15/061,389, filed Mar. 4, 2016, which (i) is a continuation of U.S.patent application Ser. No. 14/933,898, filed Nov. 5, 2015, which is acontinuation of U.S. patent application Ser. No. 14/185,610, filed Feb.20, 2014, which claims the benefit of U.S. Provisional PatentApplication No. 61/877,857, filed Sep. 13, 2013, and (ii) is acontinuation-in-part of International Application No. PCT/US2012/062831,filed Oct. 31, 2012, which claims the benefit of U.S. Provisional PatentApplication No. 61/554,377, filed Nov. 1, 2011 and U.S. ProvisionalPatent Application No. 61/703,618, filed Sep. 20, 2012, all of which areincorporated herein by reference in their entireties.

BACKGROUND

The present application relates to a cementitious composite for in-situhydration (i.e., hydration in place, on location, on a constructionsite). In-situ hydration occurs as a liquid is topically applied andreacts with a volume of cementitious material within the cementitiouscomposite. This reaction occurs while the cementitious composite is in aposition and does not change the directional orientation of thepre-fabricated nature of the cementitious composite. Such a cementitiouscomposite allows cementitious material to set and harden within thecementitious composite without requiring traditional mixing and pourprocedures.

Textile-reinforced composites may include at least one layer of a two orthree-dimensional textile and a layer of cementitious material to form alaminated composite, where traditionally the textiles are layered in aplaner form. Such laminated composites may exhibit excellent in-planeproperties but typically lack reinforcement in the thickness direction(i.e., a direction orthogonal to a surface of the composite) or havereduced bonding of the layers. While traditional cement composites mayinclude plain weave fabrics or multiple layers of fabric to improveperformance, these systems may fail (e.g., delaminate, etc.) underloading.

Other cementitious composites include “spacer fabric” composites havingmonofilament threads or yarns which are ideally elastomeric, wovenbetween two layers to create a fabric with a spaced apart arrangementconfigured to entrap cementitious material between the two layers. Theouter layers are each porous to allow the yarns, threads, etc. to bethreaded through the outer layers, where the yarns, threads, etc. arefed through the pores of the layers. Additional, less porous fabrics ormembranes may be attached to the outer layers of the spacer fabric toreduce the size of openings on each layer and prevent the cementitiousmaterial from escaping the composite. Adhesive may be required to attachthe additional, less porous fabric layers. The yarns of the spacerfabric do not provide a structure to which other layers may be attached.The yarns must be woven between porous outer layers having aperturesarranged in a set configuration designed for the yarn to thread though.Such spacer fabric cementitious composites are labor intensive tomanufacture.

SUMMARY

One embodiment relates to a cementitious composite for in-situhydration. The cementitious composite includes a first layer, a secondlayer spaced from the first layer, and a cementitious mixture disposedbetween the first layer and the second layer. The cementitious mixtureincludes cementitious materials. The cementitious mixture is configuredto absorb a mass of water that provides a maximum 28 day compressivestrength of the cementitious composite upon curing which is representedby M_(w)=x·M_(c). M_(w) is the mass of the water per unit area of thecementitious composite. M_(c) is a mass of the cementitious materials ofthe cementitious mixture per unit area of the cementitious composite. xis a ratio of the mass of the water relative to the mass of thecementitious materials of the cementitious mixture per unit area of thecementitious composite that provides the maximum 28 day compressivestrength of the cementitious composite. x is between 0.25 and 0.55.

Another embodiment relates to a cementitious composite. The cementitiouscomposite includes a first layer, a second layer spaced from the firstlayer, and a cementitious mixture disposed between the first layer andthe second layer. The cementitious mixture at least one of (i) includescolloidal cement, (ii) is compacted in a specific arrangement, and (iii)undergoes a specific treatment process to provide particles with acertain shape and size. The cementitious mixture is configured to absorba mass of water that provides a maximum 28 day compressive strength ofthe cementitious composite upon curing which is represented byM_(w)=x·M_(c)·M_(w) is the mass of the water per unit area of thecementitious composite. M_(c) is a mass of the cementitious materials ofthe cementitious mixture per unit area of the cementitious composite. xis a ratio of the mass of the water relative to the mass of thecementitious materials of the cementitious mixture per unit area of thecementitious composite that provides the maximum 28 day compressivestrength of the cementitious composite. x is between 0.15 and 3.5.

Still another embodiment relates to a method for manufacturing acementitious composite for in-situ hydration. The method includesproviding a first layer; providing a second layer; and disposing acementitious mixture between the first layer and the second layer. Thecementitious mixture is configured to absorb a mass of water thatprovides a maximum compressive strength of the cementitious compositeupon curing, where a ratio of the mass of the water relative to a massof the cementitious materials of the cementitious mixture that providesthe maximum compressive strength is between 0.25 and 0.55.

The invention is capable of other embodiments and of being carried outin various ways. Alternative exemplary embodiments relate to otherfeatures and combinations of features as may be recited herein.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosure will become more fully understood from the followingdetailed description taken in conjunction with the accompanying drawingswherein like reference numerals refer to like elements, in which:

FIG. 1 is a perspective view of operators installing a cementitiouscomposite in a canal lining application, according to an exemplaryembodiment;

FIG. 2 is an exploded perspective view of a cementitious composite,according to an exemplary embodiment;

FIG. 3 is a perspective view of a rolled cementitious composite,according to an exemplary embodiment;

FIG. 4 is a schematic cross-sectional view of the cementitious compositeof FIG. 2, according to an exemplary embodiment; and

FIG. 5 is a detailed view of a cementitious mixture within thecementitious composite of FIG. 4, according to an exemplary embodiment.

DETAILED DESCRIPTION

Before turning to the figures which illustrate the exemplary embodimentsin detail, it should be understood that the application may be notlimited to the details or methodology set forth in the description orillustrated in the figures. It should also be understood that theterminology may be for the purpose of description only, and should notbe regarded as limiting.

Composite Layers

Cementitious composite mats may provide enhanced structural performancerelative to concrete reinforced with traditional materials (e.g.,fibers, rebar, etc.), traditional unidirectional textile reinforcedconcrete composites, and woven or knitted three-dimensional textileconcrete composites. Cementitious composite mats may include a drycementitious mixture embedded in, and/or contained by, a structurallayer. The structural layer may be positioned between an impermeablelayer and a permeable layer. The cementitious mixture undergoes itsnormal setting and strength gain process after in-situ hydration toproduce a rigid composite. The permeable layer may hold water (e.g., fora controlled period of time, etc.) for improved curing of thecementitious composite mat (e.g., facilitating the release of water intothe cementitious mixture over a period of time, etc.). Unliketraditional concrete, cementitious composite mats do not require thecementitious portion to be mixed (e.g., in a standalone mixer, in acement mixer truck, etc.). The cementitious mixture of the presentapplication does not wash from the cementitious composite mat as easily(e.g., not at all, etc.) as traditional, non-formulated cementitiousmixtures and remains secured within the cementitious composite mat suchthat it hardens in place without needing to be mixed. The cementitiousmixture is disposed between the permeable and impermeable layers and mayinclude accelerators, retarders, latex modifiers, curing modifiers,other modifiers, fibers, glass additives, metal additives, stoneadditives, organic additives, water reducing admixtures, shrinkagereducing admixtures, viscosity modifiers, absorbent materials (e.g.,superabsorbent materials, superabsorbent polymers, superabsorbent clays,etc.), interconnection particles (e.g., beads, pellets, strands, etc.;made of a resin, a polymer, elastomeric polymer, PVC, polypropylene,polyethylene, a metal or metal alloy having a low melting point, etc.),adhesives, and/or other gel forming additives so the cementitiousmixture remains stationary when hydrated. A cementitious mixture thatremains stationary facilitates using a top layer (e.g., permeable layer,etc.) that dissolves upon hydration and/or that has apertures.

The structural layer of the cementitious composite mat may be formedinto, or include an independent, free-standing material (e.g., thestructural layer, etc.). The structure layer may improve load bearingcapabilities of the cementitious composite mat by distributing theenergy of a load across the structural layer. The structure layer mayalso bridge crack faces in the cementitious phase to provide improvedcrack resistance and/or localize cracking to reduce crack propagation.The structural layer may be coupled to at least one of the permeablelayer and the impermeable layer with an adhesive, a heat treatmentprocess, and/or mechanically (e.g., barbs, fibers, etc.). In someembodiments, the structural layer is at least partially manufacturedfrom an adhesive material. In some embodiments, the cementitiouscomposite does not include the structural layer, but rather the adhesivelayer functions as a structural layer. Cementitious composite matshaving the structural layer may provide improved structural performanceper unit of volume, have a lower cost, reduce labor costs, require lessprocessing than other concrete or concrete composite, reduce thepossibility of variation in specification compared to poured concrete,and/or eliminate the disadvantages of traditional wet mixing (e.g.,range constraints for delivery with a concrete mixer vehicle, etc.),among having other advantages. In addition to holding the cementitiouscomposite mat together and/or retaining the cementitious mixture (e.g.,pre-hydration, etc.), the structural layer may structurally reinforcethe cementitious layer and/or cementitious composite mat post-hydration.

Hydration of cementitious composite mats may be initiated in-situ (e.g.,in place, on a job site, etc.). The cementitious composite mat may betransported to a location (e.g., canal, etc.) as a flexible compositematerial in a pre-packaged configuration (e.g., sheets, rolls, etc.) andhydrated on-location. Such cementitious composite materials may providecommercial, water conservation, and operational benefits. By way ofexample, cementitious composite mats may be applied to form a canallining, as shown in FIG. 1. Other applications for cementitiouscomposite mats may include the following: low to high flow channels,open-channel water conveyance canals, irrigation and drainage ditches,swales, culverts, jetties, groins, dikes, levees, reservoirs, checkdams, interceptor ditches, horizontal drains, stream restoration andstorm water management, seawall and bulkhead scour protection, landfilllayering and capping, brown field layering and capping, mine shaftreinforcement, structural reinforcement, airfield or helipadconstruction, boat launch ramps, column and beam reinforcement, piperepair, oilfield lining, holding basins, pond lining, pit lining, wastewater lagoon lining, slope fortification, snow basin fortification,tieback fortification, berm lining, beach and shoreline restoration, asa road surface, driveways, sidewalks and walkways, form work lining,concrete waterproofing, a material for homes or other structures,landscaping, foundation linings, flooring, pool construction, patioconstruction, roofs, insulation and weatherproofing, as a replacementfor stucco, for noise attenuation, and for retaining wall and embankmentconstruction, among other applications.

According to the exemplary embodiment shown in FIG. 2, a composite mat,shown as cementitious composite 10, includes a plurality of layers. Asshown in FIG. 2, such layers include a containment layer, shown aspermeable layer 20; a cementitious layer, shown as cementitious mixture30; a three-dimensional volume layer (e.g., a bunching layer, a meshlayer, a grid layer, a nonwoven layer, a not woven layer, a nonfibrouslayer, a fiberless layer, pins and/or connectors, interconnectingparticle layer, a coiled layer, a tube layer, a 3D knitted and/or wovenlayer, a plastic layer, a metal layer, a layer configured forintegration with one or more snap-fit connections, etc.), shown asstructure layer 40; an impermeable (e.g., sealing, etc.) layer, shown asimpermeable layer 50; and one or more adhesive layers, shown as adhesivelayer 60. According to an exemplary embodiment, permeable layer 20,cementitious mixture 30, structure layer 40, impermeable layer 50,and/or adhesive layer 60 are disposed adjacent to one another andassembled into a sheet to form cementitious composite 10. As shown inFIG. 2, structure layer 40 may be disposed between (e.g., sandwichedbetween, etc.) permeable layer 20, impermeable layer 50, and adhesivelayer 60. In some embodiments, the cementitious composite 10 does notinclude structure layer 40. In such embodiments, adhesive layer 60 mayfunction as a structure layer. According to an exemplary embodiment,cementitious composite 10 has a thickness of between five millimetersand one hundred millimeters pre-hydration. The thickness of cementitiouscomposite 10 may exceed the pre-hydration thickness after hydrationwhen, by way of example, additives are included in cementitious mixture30 (e.g., expansive cement, etc.). It should be understood thatreference to a structure layer, an adhesive layer, and/or a cementitiousmixture may include any structure layer, adhesive layer, and/orcementitious mixture disclosed herein.

According to an exemplary embodiment, cementitious composite 10 includeslayers that are coupled together. Such coupling may reduce the relativemovement between the layers pre-hydration (e.g., during themanufacturing process, during transportation, during installation,etc.). By way of example, impermeable layer 50 may be coupled (e.g.,selectively joined, etc.) with structure layer 40 and/or cementitiousmixture 30 with adhesive layer 60. By way of another example, permeablelayer 20 may be coupled (e.g., selectively joined, etc.) with structurelayer 40 and/or cementitious mixture 30 with adhesive layer 60. Suchcoupling may improve the structural characteristics of cementitiouscomposite 10 by facilitating load transfer between permeable layer 20,structure layer 40, adhesive layer 60, and/or impermeable layer 50.Adhesive layer 60 and/or structure layer 40 may serve as a bondingmedium. Various structure layers and/or adhesive layers may reduce therisk of delamination.

According to various embodiments, cementitious composite 10 includes adifferent combination of layers. By way of example, cementitiouscomposite 10 may include impermeable layer 50, structure layer 40,adhesive layer 60, cementitious mixture 30, and/or permeable layer 20.Such a composite may utilize the structure layer 40 and/or the adhesivelayer 60 to hold cementitious mixture 30, may include a removable layerto retain cementitious mixture 30 during transport and in theapplication of cementitious composite 10, and/or may include anothersystem designed to retain cementitious mixture 30. According to variousalternative embodiments, cementitious composite 10 includes permeablelayer 20 and impermeable layer 50, only impermeable layer 50, onlypermeable layer 20, or neither permeable layer 20 nor impermeable layer50. By way of example, cementitious composite 10 may include impermeablelayer 50, structure layer 40, adhesive layer 60, cementitious mixture30, and permeable layer 20. By way of another example, cementitiouscomposite 10 may include impermeable layer 50, structure layer 40,adhesive layer 60, and cementitious mixture 30. By way of yet anotherexample, cementitious composite 10 may include impermeable layer 50,adhesive layer 60, cementitious mixture 30, and permeable layer 20. Byway of still another example, the cementitious composite 10 may includeimpermeable layer 50 and adhesive layer 60, and cementitious mixture 30may be introduced thereon on-site (e.g., cementitious mixture 30 may bescattered, laid, embedded, etc. across, in, and/or along impermeablelayer 50 on-site and prior to in-situ hydration, etc.). Further,impermeable layer 50 may have one or more surface imperfections and/or aroughness (e.g., fibers, members, barbs, etc.) that are configured tofacilitate holding cementitious mixture 30 prior to and/or afterhydration, attach to the hardened concrete, and/or be embedded withinthe hardened concrete.

Referring next to the exemplary embodiment shown in FIG. 3, cementitiouscomposite 10 may be arranged into a flexible sheet. As shown in FIG. 3,permeable layer 20, structure layer 40, and impermeable layer 50 areeach flexible and disposed adjacent to one another. According to anexemplary embodiment, such a combination of flexible layers facilitatesrolling cementitious composite 10 to facilitate transportation andreduce the amount of cementitious mixture 30 that migrates throughpermeable layer 20. According to an alternative embodiment, cementitiouscomposite 10 may be arranged in another configuration (e.g., varioussheets that may be stacked, a sheet having a pre-formed shape, etc.).

Structure Layer

Structure layer 40 may include low density, high void space, anddiscontinuities, among other characteristics. In one embodiment,structure layer 40 is an independent, structural material configured tosupport the weight of cementitious mixture 30, thereby reducing the riskof pre-hydration delamination (e.g., separation of structure layer 40from impermeable layer 50, from permeable layer 20, from adhesive layer60, etc.), while improving the strength of the cementitious composite 10post-hydration. By way of example, structure layer 40 may be configuredto independently support a cementitious mix having a weight of betweenone and five pounds per square foot. These characteristics improve thestrength and transportability, among other features, of cementitiouscomposite 10. Structure layer 40 may also reduce the prevalence and/orseverity of shrink-induced cracking within cementitious mixture 30. Sucha reduction may be produced because structure layer 40 limits crackpropagation by bridging crack faces within the cementitious phase.

According to an exemplary embodiment, structure layer 40 is flexible. Inother embodiments, structure layer 40 is semi-rigid. By way of example,structure layer 40 may have a predefined shape (e.g., curved, etc.) suchthat cementitious composite 10 takes the shape of structure layer 40. Insome embodiments, structure layer 40 is deformable (e.g., plasticallydeformable, etc.). According to an exemplary embodiment, structure layer40 includes at least one of a natural material (e.g., coconut fiber,cellulose fiber, other natural materials, etc.), a synthetic material(e.g., aramid glass, etc.), a polymeric material, (e.g., plastic, nylon,polypropylene, etc.), a metallic material (e.g., metal, aluminum oxide,etc.), and a composite material (e.g., carbon fiber, silicon carbide,etc.).

According to an exemplary embodiment, structure layer 40 may haveindependent mechanical properties apart from those of the other layersof cementitious composite 10. By way of example, such mechanicalproperties may include tensile strength, elongation at break, and tearstrength, among other known properties. Structure layer 40 may haveportions with a target thickness, length, and/or coupling designed toprovide target mechanical properties. Structure layer 40 may have acomposition that provides a target mechanical property. The modulus ofelasticity and geometry of structure layer 40 may affect the flexibilityof cementitious composite 10. A structure layer 40 having one of a lowermodulus of elasticity or more open geometry may increase the pliability(e.g., lower radius of curvature, etc.) of cementitious composite 10(e.g., for shipping, to contain cementitious mixture 30, etc.).

According to an alternative embodiment, structure layer 40 includes voidpatterns (e.g., shapes cut through structure layer 40, three dimensionalvoids formed within structure layer 40, etc.). Such void patterns may beformed in structure layer 40 through cutting, forming, or anotherprocess. The void patterns may be formed during the primarymanufacturing of structure layer 40 or subsequently as a secondarymanufacturing process. According to an exemplary embodiment, the voidpatterns are randomly distributed or formed in sequence (e.g., ahoneycomb, etc.). The void patterns may decrease the time required todispose cementitious mixture 30 in structure layer 40, improve thephysical properties of cementitious composite 10 after in-situhydration, and/or provide other advantages.

According to an alternative embodiment, a coating may be disposed aroundand/or along at least a portion of structure layer 40. By way ofexample, the coating may be configured to improve various properties(e.g., strength, durability, etc.) of structure layer 40. As still afurther example, the coating may improve the coupling strength ofportions within structure layer 40, of structure layer 40 to permeablelayer 20, impermeable layer 50, and/or adhesive layer 60, and ofstructure layer 40 to cementitious mixture 30 after in-situ hydration.By way of example, the coating may include an abrasive coating (e.g.,similar to that provided with a Scotch-Brite® scouring pad, etc.), acoating to provide resistance to ultraviolet light, a coating to protectstructure layer 40 from cementitious mixture 30 (e.g., improved alkalineresistance, improved bonding to cementitious mixture 30 post-hydration,to reduce delamination and/or detachment from set cementitious mixture30, etc.), and/or still another known coating.

In some embodiments, cementitious composite 10 includes a scrim lining(e.g., a mesh reinforcing material, a grid reinforcing material, ageotextile, a geogrid, a nonwoven material, a woven material, etc.)coupled to (e.g., fused, integrally formed, joined, etc.) structurelayer 40. A scrim lining may be coupled to one or more surfaces ofstructure layer 40 or disposed within structure layer 40. By way ofexample, the scrim lining may be disposed along a top surface (e.g., thetopmost, etc.) of structure layer 40, disposed along a bottom surface(e.g., the bottommost, etc.) of structure layer 40, disposed within amiddle portion of structure layer 40, disposed along an edge ofstructure layer 40, extending diagonally within structure layer 40, etc.The scrim lining may be a similar material as permeable layer 20 toimprove bonding between permeable layer 20 and structure layer 40 (e.g.,when the scrim is disposed along the bonding interface, etc.). The scrimlining may improve the tensile strength of structure layer 40 andcementitious composite 10 both before and after in-situ hydration. Byway of example, a loosely assembled structure layer 40 may have atendency to separate, and a scrim lining may reinforce structure layer40 to prevent such separation. The scrim lining may decrease the risk ofdelamination of permeable layer 20 and/or impermeable layer 50 therefrom(e.g., when the scrim lining is positioned on the top and/or the bottomof structure layer 40, etc.).

According to various exemplary embodiments, structure layer 40 mayinclude one or more of: a bunching layer, a mesh layer, a grid layer, anonwoven layer, a not woven layer, a nonfibrous layer, a fiberlesslayer, pins and/or connectors, an interconnecting particle layer, acoiled layer, a tube layer, a 3D knitted and/or woven layer, a plasticlayer, a metal layer, and/or a layer configured for integration with oneor more snap-fit connections.

Cementitious Mixture

According to the exemplary embodiment shown in FIGS. 4 and 5,cementitious mixture 30 is disposed within at least a portion ofstructure layer 40 and/or adhesive layer 60. As shown in FIGS. 4 and 5,cementitious mixture 30 includes a mixture of constituents (e.g.,materials, etc.), shown as cementitious materials 32. Cementitiousmaterials 32 may include cement (e.g., Portland cement, Alumina cement,CSA cement, etc.) and/or supplementary cementitious materials (e.g., flyash, silica fume, slag, metakaolin, other supplementary materials,etc.). Cementitious mixture 30 may further include aggregate materialsor other filler particles (e.g., fine aggregates, coarse aggregates,sand, limestone, non-absorbent materials, etc.), shown as aggregates 34.In one embodiment, aggregates 34 are uniformly (e.g., evenly, etc.)distributed throughout cementitious mixture 30. In other embodiments,aggregates 34 are non-uniformly (e.g., randomly, unevenly, etc.)distributed throughout cementitious mixture 30. Aggregates 34 may havesizes between greater than thirty mesh (i.e., 595 microns) and less thanfive mesh (i.e., 4000 microns). In some embodiments, aggregates 34 havesizes between three-hundred mesh (i.e., 50 microns) and thirty mesh. Thesize of aggregates 34 may be selected to create a desired size andamount of void space within cementitious mixture 30. The size and amountof void space within cementitious mixture 30 may directly affect waterflow during in-situ hydration of cementitious composite 10.

In some embodiments, cementitious mixture 30 includes additives (e.g.,fibers, plasticizers, accelerators, retarders, viscosity modifiers,absorbers, water reducers, etc.). Such additives may be used to improvethe mechanical properties (e.g., strength, setting time, curingrequirements, thermal coefficient of expansion, permeability, acidresistance, etc.) or durability, among other characteristics, of thecementitious mixture 30 and/or may be used as a substitute for a portionof cementitious materials 32. According to an exemplary embodiment, theadditives include a pozzolonic material (e.g., fly ash, bottom ash,silica fume, slag, metakaolin, etc.) added at a specified mix ratio.

As shown in FIGS. 4 and 5, cementitious mixture 30 includes an absorbentmaterial, shown as absorbent material 36. According to an exemplaryembodiment, absorbent material 36 is configured to absorb water andexpand during in-situ hydration to lock cementitious materials 32 and/oraggregates 34 in place (e.g., increases the stability and/or viscosityof cementitious mixture 30 within structure layer 40, adhesive layer 60,etc.) to prevent washout of cementitious mixture 30 from cementitiouscomposite 10 during hydration. Absorbent material 36 may therebyfacilitate applying and topically hydrating cementitious composite 10 onslopes (e.g., hillsides, ditches, etc.) without the risk of washing outcementitious mixture 30 from the structure layer during hydration.Absorbent material 36 may additionally or alternatively improve curingof cementitious composite 10 by providing or releasing water from withincementitious mixture 30 during the curing process. Improving the curingof cementitious composite 10 may improve (e.g., increase, maximize,etc.) the strength thereof (e.g., up to double that of a cementitiouscomposite having a mix that does not include absorbent material, etc.).Absorbent material 36 may additionally or alternatively improve one ormore post-hydration and post-cure properties of cementitious composite10 (e.g., abrasion resistance, flexural strength, puncture strength,compressive strength, etc.). Absorbent material 36 may additionally oralternatively hold water to reduce evaporation, release water over aperiod of time, and/or control the water to cement ratio.

According to an exemplary embodiment, cementitious mixture 30 includesapproximately 0.001-5% (e.g., by weight, by volume, etc. of cementitiousmixture 30) of absorbent material 36. Absorbent material 36 may includeparticles, pellets, powder, fiber, a membrane, microbeads, etc. In someembodiments, absorbent material 36 includes an absorbent materialconfigured to absorb between 0.001 and 1 times its weight in water. Insome embodiments, absorbent material 36 includes a superabsorbentmaterial configured to absorb between 1 and 1000 times its weight inwater. In one embodiment, the superabsorbent material is configured toabsorb between 75 and 300 times its weight in water, for exampleapproximately 200 times its weight in water. The superabsorbent materialmay include a superabsorbent polymer (SAP). The SAP may include sodiumpolyacrylate, poly-acrylic acid sodium salt, polyacrylamide copolymer,ethylenemaleic anhydride copolymer, cross-linked carboxymethylcellulose,polyvinyl alcohol copolymers, cross-linked polyethylene oxide, and/orstarch grafted copolymer of polyacrylonitrile, among other possibleSAPs. The superabsorbent material may additionally or alternativelyinclude a superabsorbent clay (e.g., to form a SAP composite (SAPC),etc.). The superabsorbent clay may include montmorillonite and/or othersubstances used to create a SAPC.

According to an exemplary embodiment, absorbent material 36 has aparticle size that may range from 1 micron to 5000 microns. In oneembodiment, the majority of absorbent material 36 has a particle sizebetween 90 microns and 300 microns at a specified mix ratio. By way ofexample, the specified mix ratio of absorbent material 36 may include0-30% of particles having a size less than 90 microns (e.g.,approximately 7%, etc.), 10-60% of particles having a size between90-150 microns (e.g., approximately 37%, etc.), 25-80% of particleshaving a size between 150-300 microns (e.g., approximately 56%, etc.),and 0-30% of particles having a size greater than 300 microns (e.g.,approximately 0%, etc.). Applicant has discovered that larger particlesof absorbent material 36 (e.g., particles having a size greater than 150microns, etc.) provide improved washout resistance relative to smallerparticles of absorbent material 36 (e.g., particles less than 150microns, etc.). By way of example, the larger particles may absorb watermore quickly and form a gel-like substance during and/or post-hydrationthat locks cementitious materials 32 and aggregates 34 within structurelayer 40 and/or adhesive layer 60 of cementitious composite 10 toprevent washout thereof. Quicker absorption of water may be advantageousas cementitious composite 10 may be topically hydrated quickly, on aslope, and/or at a relatively high pressure. Applicant has alsodiscovered that the smaller particles of absorbent material 36 improvethe curing process of cementitious composite 10 (e.g., increasing thestrength thereof, etc.). Applicant has also discovered that smallerparticles create a finer, less abrasive material after hydration withlower permeability.

In some embodiments, cementitious mixture 30 includes lime (e.g.,hydrated lime, etc.). By way of example, cementitious mixture 30 mayinclude absorbent material 36, lime, or both absorbent material 36 andlime. Applicant has discovered that lime stiffens and sets quickly(e.g., almost instantaneously with the proper mix ratios of lime)relative to one or more other constituents of cementitious mixture 30.Applicant has further discovered that the quick-setting lime locks oneor more of the other constituents of cementitious mixture 30 in place,thereby reducing washout of cementitious mixture 30 during hydration.According to an exemplary embodiment, cementitious mixture 30 includesapproximately 0.01 to greater than 30% (e.g., by weight of cementitiousmixture 30) of lime. In one embodiment, cementitious mixture 30 includesapproximately 2-5% (e.g., by weight of cementitious mixture 30) of lime.

In some embodiments (e.g., embodiments in which cementitious mixtureincludes lime, etc.), cementitious mixture 30 includes fibers (e.g.,fine fibers, etc.). In other embodiments, fibers may be used incombination with the absorbent material 36 in cementitious mixture 30without the addition of lime. The fibers may advantageously reducecracking of cementitious composite 10. According to an exemplaryembodiment, cementitious mixture 30 includes fibers having sizes between0.05 millimeters (mm) and 20 mm. Applicant has discovered that fiberssized less than 1 mm have the greatest impact on crack prevention.According to an exemplary embodiment, cementitious mixture 30 includesapproximately 0.05-2.5% (e.g., by weight of cementitious mixture 30) offibers. In other embodiments, cementitious mixture 30 has a greater orlesser amount of fibers. The fibers may be manufactured from a syntheticmaterial (e.g., polypropylene, polyethylene, nylon, glass, polyester,acrylic, aramid, etc.) and/or natural material (e.g., cellulose fiber,coconut fiber, grass, etc.). The fibers may be a monofilament,fibrillated, and/or have another structure. According to an exemplaryembodiment, cementitious mixture 30 having lime, fibers, and/orabsorbent material 36 provides improved performance of cementitiouscomposite 10 in terms of increased washout prevention, decreasedcracking, improved curing, increased strength (e.g., ultimate strength,flexural strength, puncture strength, compressive strength, etc.), etc.

In some embodiments, an adhesive (e.g., a liquid adhesive, a geladhesive, etc.) is mixed with other constituents of cementitious mixture30. By way of example, the adhesive may facilitate forming (as part ofcementitious mixture 30) a tacky layer to which impermeable layer 50and/or permeable layer 20 may be attached. The tacky layer may bebetween one tenth and four inches thick. Impermeable layer 50 and/orpermeable layer 20 may be coupled along top and/or bottom sides ofcementitious mixture 30 with the adhesive. In one embodiment, theadhesive is water permeable. In other embodiments, the adhesive isremoved (e.g., heated off, etc.) and/or cured to facilitate hydration ofthe cementitious particles of cementitious mixture 30 before or afterimpermeable layer 50 and/or permeable layer 20 are attached. By way ofexample, 50, 80, or 95 percent (e.g., by area, by volume, by weight,etc.) of the adhesive may be removed and/or cured to facilitatehydration.

According to an exemplary embodiment, the sizes of aggregates 34, thesize of cementitious materials 32, the size of absorbent material 26,the size of other additives (e.g., lime, fibers, accelerators,retarders, adhesive, etc.), and/or amount of compaction of cementitiousmixture 30 are selected to create a desired size and/or amount of voidspace, shown as voids 38, within cementitious mixture 30. The size andamount of voids 38 within cementitious mixture 30 may directly affectwater flow during in-situ hydration of cementitious composite 10.

According to an exemplary embodiment, the materials of cementitiousmixture 30 are mixed together and thereafter disposed along or betweenimpermeable layer 50, adhesive layer 60, and/or permeable layer 20. Inone embodiment, cementitious mixture 30 is positioned within voids ofstructure layer 40 and/or adhesive layer 60 using gravity, vibration,and/or compaction. Cementitious mixture 30 may be disposed intostructure layer 40 and/or adhesive layer 60, and along impermeable layer50 with a uniform thickness (e.g., 0.25″, 0.5″, 0.75″, etc.). In someembodiments, permeable layer 20 is disposed along cementitious mixture30 before compaction such that cementitious mixture 30 is compressedbetween permeable layer 20 and impermeable layer 50. The compression maybe applied to facilitate even distribution of the constituents (e.g.,absorbent material 36, aggregates 34, cementitious materials 32,additives, etc.) within cementitious mixture 30 and/or affect the sizingof the voids 38 within cementitious mixture 30. Compaction may befacilitated or replaced with vibration. The compression may alsoincrease the structural performance of the cementitious mixture 30post-hydration. The extent that cementitious mixture 30 is compacted mayimpact the risk of cementitious mixture 30 washing out from cementitiouscomposite 10 (e.g., reduce the risk of washout, etc.), the ability ofwater to flow through cementitious mixture 30, the time required forhydration, setting, and hardening of cementitious mixture 30, thestrength of cementitious composite 10, and/or the risk of cementitiousmaterials 32, aggregates 34, and/or absorbent materials 36 migrating outof cementitious composite 10. In some embodiments, an absorbent material(e.g., absorbent material 36, etc.) is additionally or alternativelycoupled to, sprayed onto, bonded to, and/or otherwise attached to (e.g.,integrally formed with, etc.) permeable layer 20, structure layer 40,adhesive layer 60, and/or impermeable layer 50. The absorbent materialmay improve (e.g., further improve, etc.) curing of cementitious mixture30.

According to an exemplary embodiment, cementitious mixture 30 includesmaterials (e.g., cementitious materials 32, etc.) that set and hardenonce exposed to a fluid (e.g., water, etc.) through a hydration process.According to an exemplary embodiment, cementitious mixture 30 isdisposed and/or compressed between permeable layer 20 and impermeablelayer 50, and undergoes a normal setting and hardening process afterin-situ hydration. The setting process may begin once cementitiousmixture 30 interacts with a fluid (e.g., water, etc.). Such hydrationand setting processes change cementitious mixture 30 from a flexible toa rigid material. While setting produces a rigid material, curing mayimprove the strength of cementitious composite 10. According to anexemplary embodiment, cementitious mixture 30 has a compressive strengthof up to ten thousand or more pounds per square inch. According to analternative embodiment, cementitious mixture 30 is modified with highperformance cementitious ingredients and additives to achieve strengthvalues in excess of ten thousand pounds per square inch.

According to an exemplary embodiment, water is added to cementitiousmixture 30 to initiate the hydration processes. An operator maytopically apply water to the surface of cementitious composite 10in-situ to hydrate cementitious mixture 30. In some embodiments,cementitious composite 10 accommodates hydration even when positioned ona horizontal, positioned at an angle, or positioned over a curvedsurface without undermining the strength of cementitious composite 10.According to an exemplary embodiment, cementitious composite 10 may behydrated even if positioned at up to a 90 degree angle relative tolevel. In these or other embodiments, cementitious mixture 30 may setwithout segregating from cementitious composite 10. In embodiments wherepermeable layer 20 does not dissolve quickly, cementitious composite 10may be hydrated in an inverted position. By way of example, cementitiouscomposite 10 may be implemented in a tunnel application where thecementitious composite 10 is used to form the walls and/or ceiling ofthe tunnel.

The characteristics of the hydrated cementitious composite 10 may beaffected by at least one of (i) the particle size of absorbent material36, aggregates 34, and/or cementitious materials 32 of cementitiousmixture 30, (ii) the characteristics of adhesive layer 60 (e.g.,structure, type, etc.), and (iii) the size, shape, diameter, materialcomposition, pattern, structure (e.g., bunching, nonwoven, not woven,grid, interconnecting particles, connectors, etc.) of structure layer40. By way of example, particle size and density may affect thehomogeneity of cementitious mixture 30 thereby impacting variousproperties (e.g., strength, flexibility, etc.) of cementitious composite10. According to an exemplary embodiment, cementitious materials 32 ofcementitious mixture 30 have an approximately equal particle size (e.g.,within 150 microns, etc.). According to an alternative embodiment,cementitious materials 32 of cementitious mixture 30 may have differentsizes (e.g., a variation of more than 150 microns, etc.) that varybetween 0.5 and 450 microns. A cementitious mixture 30 havingdifferentially-sized particles may improve packing and reduce open space(i.e., voids 38) within cementitious mixture 30.

According to an exemplary embodiment, cementitious mixture 30 is curedusing an external curing process. By way of example, such externalcuring may include water ponding. According to various alternativeembodiments, the external curing process includes water spraying, wetburlap, sheeting, curing compounds, absorbent sands, and acceleratedcuring, among other known methods. In some embodiments, permeable layer20 is formed of a hydrophilic material (e.g., paper, cellulose basedmaterials, etc.) that may improve curing by holding water to prolongexposure of cementitious mixture 30 to a fluid. In some embodiments,permeable layer 20 includes a water soluble material which holds waterand only dissolves with warm or hot water (e.g., greater than 70, 80,90, 100, 110, 120, 130, etc. degrees Fahrenheit, etc.). Such a permeablelayer 20 may thereby hold water for a desired period of time whilehydrating cementitious mixture 30 and may thereafter be removed (e.g.,disintegrated, detached, etc.) using warm or hot water. According to analternative embodiment, permeable layer 20 is formed of a coatingmaterial having fewer apertures to improve curing by reducing theevaporation of water from cementitious mixture 30.

According to still another alternative embodiment, cementitious mixture30 is cured using an internal curing process. According to an exemplaryembodiment, cementitious mixture 30 is cured using internal water curingwhere cementitious mixture 30 includes a component that serves as acuring agent to the cementitious mixture. Such a component may includeeither absorbent material 36, an aggregate, or a new component (e.g. anadditive, superabsorbent polymer, special aggregate, etc.) introducedinto cementitious mixture 30 during the manufacturing process. Further,hydrophilic additives (e.g., absorbent material 36, superabsorbentpolymers, etc.) may improve curing by facilitating the ingress of waterwithin cementitious mixture 30. According to an alternative embodiment,structure layer 40 and/or adhesive layer 60 are hydrophilic (e.g.,absorbent, etc.) and facilitate the absorption of water intocementitious mixture 30. In some embodiments, cementitious mixture 30includes interconnection particles that join together upon activation(e.g., heating, etc.) to form structure layer 40.

Adhesive Layer

According to an exemplary embodiment, adhesive layer 60 is applied tocouple (e.g., connect, etc.) permeable layer 20 and impermeable layer 50to cementitious mixture 30, structure layer 40, and/or each other. Insome embodiments, adhesive layer 60 is applied to couple permeable layer20 and impermeable layer 50 together, without adhesively couplingpermeable layer 20 and/or impermeable layer 50 to cementitious mixture30 and/or structure layer 40. In some embodiments, adhesive layer 60 isconfigured to fully serve the function of structure layer 40 (e.g.,replace and provide the benefits of structure layer 40, such thatcementitious composite 10 does not need structure layer 40, to connectpermeable layer 20 and impermeable layer 50 to cementitious mixture 30and/or to each other, to hold cementitious composite 10 together whenhandling, etc.). Adhesive layer 60 may include various materialsincluding one or more of hot melt, APO/APAO, PUR, polyurethane, otherhot melts, animal glue, single component adhesive, multi componentadhesive, epoxy, other adhesives, rubbers, silicon adhesives,cyanoacrylate adhesives, Solvent Cements, 3M 94ca, DHM Adhesives 4291,etc. According to an exemplary embodiment, the adhesive of adhesivelayer 60 is a non-water based adhesive such that cementitious materials32 of cementitious mixture 30 are not activated, or are minimally orpartially activated, when adhesive layer 60 comes into contacttherewith. Aggregates 34 and other larger particles within cementitiousmixture 30 (e.g., particles other than cementitious materials 32, sand,other granules, etc.) may be configured to facilitate adhesive bonding.

Adhesive layer 60 may have a permanent bond strength and may have ashort open time (e.g., tacky for a predefined period of time whenexposed to air; one minute, two minutes, five minutes, ten minutes,etc.) such that the material thereof dries quickly after being deposited(e.g., onto permeable layer 20, onto impermeable layer 50, ontocementitious mixture 30, into cementitious mixture 30, etc.) to hold thevarious layers of the cementitious composite 10 together and to be ableto be rolled quickly thereafter. Heat may be applied to, over, and/oralong adhesive layer 60 after application thereof to cementitiouscomposite 10 to accelerate curing and/or hardening. Adhesive layer 60may dry to a semi-flexible form and thereby be configured to facilitaterolling of cementitious composite 10.

In some embodiments, adhesive layer 60 is applied in a specific pattern(e.g., sheet layer, grid layer, pin layer, etc.). Depending on thepattern, adhesive layer 60 may improve the structural properties ofcementitious composite 10, including, by way of example only, improvingpost cement hardening (e.g., post-hydration structural properties,etc.), increasing plasticity, improving strain hardening, reducingcracking, increasing impact strength, and/or increasing flexuralstrength, among other improvements. In one embodiment, a first adhesivelayer 60 is deposited onto impermeable layer 50, then cementitiousmixture 30 is deposited onto the first adhesive layer 60, then a secondadhesive layer 60 is deposited onto the top surface of cementitiousmixture 30, and finally permeable layer 20 is disposed along the secondadhesive layer 60. In some embodiments, structure layer 40 is disposedalong the first adhesive layer 60 prior to cementitious mixture 30 beingdeposited thereon. In another embodiment, adhesive layer 60 is appliedthrough cementitious mixture 30 (e.g., after cementitious mixture 30 isdeposited onto impermeable layer 50, with an injector device, etc.)before or after permeable layer 20 is applied.

As shown in FIG. 4, adhesive layer 60 includes a first adhesive layer,shown as lower adhesive layer 62, positioned between inner side 52 ofimpermeable layer 50 and the bottom side of structure layer 40 andcementitious mixture 30 to couple the bottom side of structure layer 40and/or cementitious mixture 30 to impermeable layer 50. As shown in FIG.4, adhesive layer 60 includes a second adhesive layer, shown as upperadhesive layer 64, positioned between inner side 22 of permeable layer20 and the top side of structure layer 40 and cementitious mixture 30 tocouple the top side of structure layer 40 and/or cementitious mixture 30to permeable layer 20. By way of example, manufacturing cementitiouscomposite 10 of FIG. 4 may include (i) providing impermeable layer 50,(ii) applying lower adhesive layer 62 along impermeable layer 50, (iii)disposing the bottom side of structure layer 40 along lower adhesivelayer 62, (iv) depositing cementitious mixture 30 into structure layer40 and along lower adhesive layer 62, (v) applying second adhesive layer64 to the top side of structure layer 40 and cementitious mixture 30,and (vi) disposing permeable layer 20 along upper adhesive layer 64. Insome embodiments, cementitious composite 10 of FIG. 4 does not includestructure layer 40.

Permeable Layer

According to the exemplary embodiment shown in FIGS. 2-4, permeablelayer 20 facilitates the dispersion of a fluid (e.g., water, etc.) intocementitious composite 10 while retaining cementitious mixture 30.Permeable layer 20 may include specified characteristics that manage theflow of the fluid through permeable layer 20. According to an exemplaryembodiment, the specified characteristics allow for the hydration ofcementitious mixture 30 without allowing cementitious materials 32,aggregates 34, absorbent material 36, and/or additives to migrate fromcementitious composite 10 (e.g., during handling before in-situhydration, during in-situ hydration, etc.). In other embodiments, thespecified characteristics may also maintain the mix ratio ofcementitious mixture 30 during the hydration and hardening processes.Further, permeable layer 20 may maintain the level of compaction ofcementitious mixture 30 by applying consistent pressure to cementitiousmixture 30. According to an exemplary embodiment, less than 10 percentby weight of cementitious mixture 30 and migrates through permeablelayer 20 prior to in-situ hydration. In some embodiments, up to 10percent by weight of cementitious mixture 30 may migrate throughpermeable layer 20 while maintaining adequate performance ofcementitious composite 10 after in-situ hydration.

According to an exemplary embodiment, permeable layer 20 includes aplurality of apertures, among other features, having a specified shape,area, frequency, and/or spacing. By way of example, the apertures mayhave a specified shape (e.g., circular, ovular, rectangular, etc.),depending on the particular application of cementitious composite 10.According to an exemplary embodiment, the size of the apertures may alsobe specified. By way of example, oversized apertures may allow sievingof cementitious mixture 30 prior to in-situ hydration. In contrast,undersized apertures may provide too slow or incomplete hydration ofcementitious mixture 30. According to an exemplary embodiment, theapertures are designed to prevent particles less than fifteen micronsfrom migrating from cementitious composite 10 and have an area ofbetween 0.001 and 3 square millimeters. According to an exemplaryembodiment, the frequency of the apertures may be specified tofacilitate the transfer of water into cementitious mixture 30. Accordingto an exemplary embodiment, permeable layer 20 includes between one andtwelve thousand apertures per square inch. According to an alternativeembodiment, permeable layer 20 is a permeable material that does notinclude apertures (e.g., a fibrous material, paper, etc.).

According to an exemplary embodiment, permeable layer 20 is coupled tostructure layer 40 and/or adhesive layer 60 during the manufacturingprocess. Such a permeable layer 20 may be designed as a removableproduct that does not remain coupled with structure layer 40 and/oradhesive layer 60 throughout the life of cementitious composite 10.According to an exemplary embodiment, permeable layer 20 includes acontainment sheet (e.g., biodegradable paper, water soluble plastic,etc.) that secures cementitious mixture 30 during the transportation ofcementitious composite 10. In some embodiments, the containment sheetmay be removed before or after the cementitious composite 10 is in placein the field. Such removal of the containment sheet may occur eitherbefore or after in-situ hydration. In either embodiment, permeable layer20 may include flow channels (e.g., perforations, etc.) designed tofacilitate the flow of water into cementitious mixture 30. In someembodiments, outer side of permeable layer 20 has a texture and/ordefines channels that are conducive to the transport of water (e.g., toremove water from outer side, to direct water from outer side, etc.).According to an alternative embodiment, permeable layer 20 is notremoved and erodes in the field from weathering without compromising thestructural performance of cementitious composite 10. According to analternative embodiment, permeable layer 20 is treated with a coating(e.g., for ultraviolet resistance, etc.) to extend service life in thefield.

According to an exemplary embodiment, inner side 22 of permeable layer20 is bonded to structure layer 40 and/or adhesive layer 60 after a heattreatment process. In one embodiment, permeable layer 20 has a meltingpoint that is greater than the melting point of structure layer 40and/or adhesive layer 60. By way of example, PVA fabric may have amelting point of between 356 and 374 degrees Fahrenheit. Permeable layer20 (e.g., a PVA fabric, etc.) may be placed in contact with portions ofstructure layer 40 and/or adhesive layer 60. Heat may be subsequentlyapplied (e.g., topically, etc.) to permeable layer 20 (e.g., with aheated roller, with a heated air stream, with a hot plate, with afurnace, etc.) to melt the ends of the portions of the structure layer40 and/or adhesive layer 60 without melting permeable layer 20, therebybonding permeable layer 20 with structure layer 40 and/or adhesive layer60.

By way of example, the applied heat may deform the portions of structurelayer 40 and/or adhesive layer 60 disposed along inner side 22 ofpermeable layer 20 (e.g., a PVA fabric, etc.). The portions of structurelayer 40 and/or adhesive layer 60 internal to cementitious mixture 30may remain intact (i.e., may not melt) even after the application ofheat. The permeable layer 20 may be in contact with cementitious mixture30 (e.g., may fuse against cementitious mixture 30, etc.) after heating,thereby retaining cementitious mixture 30, and restricting movement ofcementitious materials 32, aggregates 34, absorbent material 36, and/oradditives within cementitious composite 10. By way of example, a heatedroller or plate may be used to both heat permeable layer 20 and compresscementitious composite 10. By way of another example, a temperatureneutral roller or a cooled roller may be used to apply compression topermeable layer 20 after the application of heat. Such an additionalroller may also cool permeable layer 20. According to an alternativeembodiment, permeable layer 20 has a melting point that is less than orequal to the melting point of structure layer 40 and/or adhesive layer60.

According to an exemplary embodiment, permeable layer 20 includes awater soluble material (e.g., a cold water soluble material, etc.). Insome embodiments, the water soluble material is a fabric material or afilm material, and such fabric material may be woven or nonwoven. In oneembodiment, the fabric material is a cold water soluble nonwovenmaterial manufactured from partially hydrolyzed polyvinyl alcohol fibers(a PVA fabric). The PVA fabric may be impermeable to cementitiousmaterials, thereby reducing the migration of cementitious mixture 30from cementitious composite 10. In some embodiments, the PVA fabric ispermeable to water. In other embodiments, the PVA fabric substantiallyretains water until the water soluble material disintegrates. In stillother embodiments, the PVA fabric is substantially impermeable to wateruntil the water soluble material disintegrates. According to anexemplary embodiment, permeable layer 20 has a surface (e.g., a nonwovensurface, etc.) having a roughness selected to facilitate bonding (e.g.,a large surface roughness such that adhesive layer 60 and/or structurelayer 40 better bond to inner side 22 of permeable layer 20, etc.).According to another exemplary embodiment, permeable layer 20 is treatedwith a coating to facilitate bonding (e.g., a fusible water solubleembroidery stabilizer, “Wet N Gone Fusible®,” etc.).

Cementitious composite 10 may be positioned and hydrated in-situ.According to an exemplary embodiment, permeable layer 20 is a watersoluble material (e.g., PVA fabric, etc.). After installation ofcementitious composite 10, an operator may apply water topically tohydrate cementitious mixture 30. In one embodiment, the water solublematerial prevents displacement of cementitious mixture 30 (i.e.,prevents the cementitious material from washing away) until the watersoluble material disintegrates. Such protection may facilitate the useof higher-pressure water sources during the hydration process. Adisintegration time for the water soluble material may be selected tofacilitate hydration. By way of example, the disintegration time may beless than one minute. According to an exemplary embodiment, watersoluble material is positioned along the sides of structure layer 40,adhesive layer 60, and/or cementitious mixture 30 such that, uponapplication of water, the water soluble fabric disintegrates. Upon theapplication of water, cementitious mixture 30 begins its initial settingperiod.

In one embodiment, cementitious materials 32, absorbent material 36,and/or additives positioned along the water soluble material may beginto lock, set, or “gel” within structure layer 40 and/or adhesive layer60 to prevent washout of the mix (e.g., cementitious materials 32,aggregates 34, etc. positioned along a middle portion of cementitiousmixture 30, etc.). In another embodiment, the mix of cementitiousmaterials 32 and/or absorbent material 36 within cementitious mixture 30are designed to partially diffuse such that a small portion of the mixflows laterally outward before or during the initial setting. Suchlateral flow may facilitate the coupling of adjacent panels or rolls ofcementitious composite 10 (e.g., panels or rolls positioned along oneanother, panels or rolls touching one another, panels or rolls spacedtwo millimeters or another distance from one another, etc.). By way ofexample, cementitious materials 32, absorbent material 36, and/oradditives along the permeable layers of two adjacent panels may begin togel during the initial setting period and bond together, thereby fusingthe adjacent panels or rolls. By way of another example, cementitiousmaterials 32, absorbent material 36, and/or additives from adjacentpanels or rolls may mix together and harden to form a rigid joint. Insome embodiments, the composition of cementitious mixture 30 is designedto facilitate such lateral coupling. In one embodiment, the watersoluble material facilitates the transport of water into cementitiouscomposite 10. By way of example, the water soluble material may includeapertures to facilitate water flow, a woven configuration thattransports the water into cementitious mixture 30, or still anotherstructure. By way of another example, the surface of cementitiousmixture 30 positioned along the water soluble material may begin to geland (i) retain (e.g., reduce the migration of, contain, limit movementof, etc.) cementitious materials 32, aggregates 34, and/or additivespositioned within a middle portion of cementitious mixture 30 and/or(ii) facilitate the flow of water into cementitious mixture 30.Cementitious materials 32, absorbent material 36, and/or additiveswithin cementitious mixture 30 may be activated during and following thedisintegration process of the water soluble material. After thedisintegration time, cementitious composite 10 may have a bare surface(e.g., cementitious mixture 30 is exposed after hardening, etc.).

Impermeable Layer

Referring to the exemplary embodiment shown in FIGS. 2-4, impermeablelayer 50 includes a material capable of retaining cementitious mixture30 and hydration water without degrading after interacting withcementitious mixture 30 (e.g., cementitious materials 32, etc.).Impermeable layer 50 may serve as a base to place cementitious mixture30 over. In one embodiment, impermeable layer 50 includes a plasticbased material (e.g., polypropylene, PVC, polyolefin, polyethylene,etc.). In some embodiments, impermeable layer 50 includes the samematerial as structure layer 40. Manufacturing both impermeable layer 50and structure layer 40 from similar materials facilitates increasingbond strength between impermeable layer 50 and structure layer 40.

As shown in FIG. 4, inner side 52 of impermeable layer 50 is coupledalong a bottom surface of structure layer 40, adhesive layer 60, and/orcementitious mixture 30. Where impermeable layer 50 is positioned alongthe bottom surface of structure layer 40, adhesive layer 60, and/orcementitious mixture 30, impermeable layer 50 may experience a portionof the flexural and tensile stresses. Such a position may improve thestrength and ductility of cementitious composite 10. In someembodiments, impermeable layer 50 is a sheet that includes a flexiblematerial (e.g., to facilitate rolling cementitious composite 10, etc.)that is capable of being coupled with structure layer 40, adhesive layer60, and/or cementitious mixture 30 without allowing a fluid to seepthrough. According to an alternative embodiment, impermeable layer 50may be integrally formed with or otherwise coupled to structure layer 40and/or adhesive layer 60. According to an alternative embodiment,impermeable layer 50 may protect cementitious mixture 30 from exposureto certain chemicals (e.g., from sulfate introduced by soils in thefield, etc.). In some embodiments, outer side of impermeable layer 50includes protrusions (e.g., extensions, barbs, etc.). The protrusionsmay facilitate securing cementitious composite 10 to various substrates(e.g., dirt, grass, gravel, etc.). In some embodiments, the outer sideof impermeable layer 50 is coated with an adhesive and covered by aremovable liner. The removable liner may be removed during installationsuch that the adhesive on the outer side of impermeable layer 50attaches cementitious composite 10 to a respective substrate.

Constituent Relationships

According to an exemplary embodiment, the relationship between thevarious constituents within cementitious composite 10 (e.g., theconstituents of cementitious mixture 30, etc.) are selected such thatcementitious composite 10 facilitates water absorption to set and curecementitious mixture 30 and provides desired performance characteristicsor properties (e.g., 28 day compressive strength, etc.). Applicant hasfound that if the volume of voids 38 within cementitious mixture 30 istoo large, the amount of water that enters cementitious composite 10during in-situ hydration may be excessive, thereby overhydratingcementitious mixture 30 such that cementitious mixture 30 sets and cureswith reduced strength. Applicant has further found that if the volume ofvoids 38 within cementitious mixture 30 is too small, not enough watermay penetrate into cementitious mixture 30 during in-situ hydration suchthat portions of cementitious mixture 30 may not react with water andfail to set and cure, again reducing the strength thereof. Applicant hasfound a preferred range for a fraction of voids 38 relative tocementitious mixture 30 within cementitious composite 10 thatfacilitates appropriately hydrating cementitious mixture 30.Appropriately hydrating cementitious composite 10 facilitates providinga cementitious composite 10 having improved (e.g., optimal, etc.)performance characteristics (e.g., 28 day compressive strength, etc.).

The total volume per unit area of cementitious composite 10 may berepresented by the following expression:V _(t) =V _(p) +V _(s) +V _(a) +V _(b)  (1)where V_(t) is the total volume per unit area of cementitious composite10, V_(p) is the volume of permeable layer 20 per unit area ofcementitious composite 10, V_(s) is the volume of structure layer 40 perunit area of cementitious composite 10, V_(i) is the volume ofimpermeable layer 50 per unit area of cementitious composite 10, V_(a)is the volume of adhesive layer 60 per unit area of cementitiouscomposite 10, and V_(b) is the bulk volume of cementitious mixture 30within cementitious composite 10 including cementitious materials 32,aggregates 34, absorbent material 36, voids 38, and/or otherconstituents (e.g., additives, limes, fibers, retarders, accelerators,etc.) that may be provided as part of cementitious mixture 30 per unitarea of cementitious composite 10.

The total mass per unit area of cementitious composite 10 may berepresented by the following expression:

$\begin{matrix}{M_{t} = {M_{p} + M_{s} + M_{i} + M_{a} + M_{c} + {\sum\limits_{i}^{n}M_{{nc}_{i}}}}} & (2)\end{matrix}$where M_(t) is the total mass per unit area of cementitious composite10, M_(p) is the mass of permeable layer 20 per unit area ofcementitious composite 10, M_(s) is the mass of structure layer 40 perunit area of cementitious composite 10, M_(t) is the mass of impermeablelayer 50 per unit area of cementitious composite 10, M_(a) is the massof adhesive layer 60 per unit area of cementitious composite 10, M_(c)is the mass of cementitious materials 32 provided as part ofcementitious mixture 30 per unit area of cementitious composite 10, andM_(nc) _(i) is the mass of each individual type of constituent of thenon-cementitious materials (e.g., aggregates 34, absorbent material 36,additives, lime, fibers, retarders, accelerators, etc.) provided as partof cementitious mixture 30 per unit area of cementitious composite 10,which may be totaled to get the total mass of the non-cementitiousmaterials. The maximum total mass of cementitious composite 10 per unitarea may be predetermined by shipping and handling requirements. In oneembodiment, the maximum total mass of cementitious composite 10 per unitarea is selected such that cementitious composite 10 has a maximum totalweight of approximately two pounds per square foot. In otherembodiments, the maximum total weight of cementitious composite 10 perunit area is greater than or less than two pounds per square foot (e.g.,1, 1.25, 1.5, 1.75, 2.25, 2.5, 2.75, 3, 4, 5, etc. pounds per squarefoot, etc.).

The bulk volume of cementitious mixture 30 per unit area may berepresented by the following expression:V _(b) =V _(c) +V _(nc) +V _(v)  (3)where V_(c) is the volume of cementitious materials 32 withincementitious mixture 30 per unit area of cementitious composite 10,V_(nc) is the volume of the non-cementitious materials withincementitious mixture 30 per unit area of cementitious composite 10, andV_(v) is the volume of voids 38 within cementitious composite 10 betweenall of the constituent materials (e.g., cementitious materials 32 andthe non-cementitious materials including aggregate 34, absorbentmaterial, additives, etc.) of cementitious mixture 30 per unit area ofcementitious composite 10. In some embodiments, the volume of thenon-cementitious material and/or the mass of the non-cementitiousmaterial within cementitious mixture 30 is negligible.

The volume of the cementitious materials 32 of cementitious mixture 30per unit area may be represented by the following expression:

$\begin{matrix}{V_{c} = \frac{M_{c}}{\rho_{c}}} & (4)\end{matrix}$where ρ_(c) is the density of cementitious materials 32 of cementitiousmixture 30. The volume of the non-cementitious materials per unit areamay similarly be represented by the following expression:

$\begin{matrix}{V_{nc} = {\sum\limits_{i}^{n}\frac{M_{{nc}_{i}}}{\rho_{{nc}_{i}}}}} & (5)\end{matrix}$where ρ_(nc) _(i) is the density of each individual type of constituentof the non-cementitious materials of cementitious mixture 30. Thedensity of cementitious materials 32 and/or the density of thenon-cementitious materials of cementitious mixture 30 may be determinedbased on the combined specific gravity of the respective constituentsthereof. The combined specific gravity may be determined based on (i)the specific gravity of each individual type of constituent withincementitious materials 32 and/or the non-cementitious material and (ii)the volume fraction of each individual type of constituent withincementitious materials 32 and/or the non-cementitious material (e.g.,aggregate 34, absorbent material, etc.) relative to the total volume ofthe constituents of cementitious materials 32 and/or thenon-cementitious material, respectively, per unit area of cementitiouscomposite 10.

The ratio of the volume of voids 38 within cementitious mixture 30relative to the volume of cementitious materials 32 provided as part ofcementitious mixture 30 may provide a void fraction represented by thefollowing expression:

$\begin{matrix}{F_{v} = {\frac{V_{v}}{V_{c}} = {\frac{V_{v}}{\frac{M_{c}}{\rho_{c}}} = {V_{v} \cdot \frac{\rho_{c}}{M_{c}}}}}} & (6)\end{matrix}$where F_(v) is the void fraction for cementitious mixture 30 per unitarea of cementitious composite 10 (i.e., the ratio of the volume ofvoids 38 within cementitious mixture 30 relative to the volume ofcementitious materials 32 of cementitious mixture 30).

Solving for the volume of voids 38 in Equation (6) and then substitutingthe volume of voids 38 from Equation (6), the volume of non-cementitiousmaterials in Equation (5), and the volume of cementitious materials 32in Equation (4) into Equation (3) results in the following expression:

$\begin{matrix}{V_{b} = {{\frac{M_{c}}{\rho_{c}} + {\sum\limits_{i}^{n}\frac{M_{{nc}_{i}}}{\rho_{{nc}_{i}}}} + {F_{v} \cdot \frac{M_{c}}{\rho_{c}}}} = {{\frac{M_{c}}{\rho_{c}}\left( {1 + F_{v}} \right)} + {\sum\limits_{i}^{n}\frac{M_{{nc}_{i}}}{\rho_{{nc}_{i}}}}}}} & (7)\end{matrix}$

Applicant has determined and confirmed experimentally that cementitiouscomposite 10 has unexpected enhanced performance (e.g., a maximum 28-daycompressive strength, etc.) when the void fraction, per unit area ofcementitious composite 10, for cementitious mixture 30 is within thefollowing range:0.64≤F _(v)≤1.35  (8)Applicant has determined that a cementitious mixture 30 having a voidfraction less than 0.64 leads to cementitious mixture 30 being overlydense such that water does not adequately permeate through cementitiouscomposite 10 and properly activate cementitious materials 32 and theother constituents of cementitious mixture 30. Applicant has alsodetermined that cementitious mixture 30 having a void fraction greaterthan 1.35 leads to cementitious mixture 30 being too loose such that theresultant hydrated cementitious composite 10 has an undesirably lowstrength. Further, if the void fraction exceeds 1.35, cementitiouscomposite 10 does not hold together upon hydration. By providingcementitious composite 10 with cementitious mixture 30 having a voidfraction between 0.64 and 1.35, cementitious composite 10 can beadequately and properly hydrated such that cementitious composite 10exhibits enhanced post-hydration and post-cure properties (e.g., maximum28-day compressive strength, etc.). In some embodiments, the voidfraction that provides the enhanced post-hydration and post-cureproperties is greater than 0.80 (i.e., between 0.80 and 1.35). In someembodiments, the void fraction that provides the enhanced post-hydrationand post-cure properties is less than 1 (i.e., between 0.64 and 1). Insome embodiments, the void fraction that provides the enhancedpost-hydration and post-cure properties is between 0.90 and 1.25. Insome embodiments, the void fraction that provides the enhancedpost-hydration and post-cure properties is between 0.95 and 1.2. In someembodiments, the void fraction that provides the enhanced post-hydrationand post-cure properties is between 1 and 1.15.

According to another embodiment, cementitious composite 10 has a voidfraction between 0.30 and approximately 0.64. Such a cementitiouscomposite 10 may be used in applications involving high pressurehydration (e.g., hydration with a jet stream, hydration with a powerwasher, hydration with a high pressure hydration source, etc.). Such alow amount of void space (i.e., high compaction) may facilitateproviding a thinner end product to facilitate more efficient packagingand shipping. The high pressure hydration may effectively break upcementitious mixture 30 having such a high amount of compaction (i.e.,low void fraction) to facilitate adequate hydration (e.g., the highpower hydration breaks down the compaction, effectively creating morevoid space, etc.). A cementitious composite 10 having a void fractionfrom 0.64 to 1.35 may be adequately hydrated using low pressurehydration (e.g., with a standard hose, with a lower pressure hydrationsource, etc.).

According to another embodiment, cementitious composite 10 has a voidfraction between 0.10 and 5.0. Such a cementitious composite 10 may havea cementitious mixture 30 that at least one of (i) includes colloidalcement, (ii) is compacted in a specific arrangement, and (iii) undergoesa specific treatment process to provide particles of varying size and/orshape. By way of example, cementitious mixture 30 may be mixed in acolloidal and/or high shear mixer that may facilitate using a lesseramount water to adequately hydrate cementitious mixture 30. By way ofanother example, cementitious mixture 30 may undergo a specialtyconstituent treatment process. For example, the constituents ofcementitious mixture 30 may be milled or graded into particles ofvarying size and/or shape before being mixed together.

Applicant has also determined and confirmed experimentally a mass ofwater per unit area relative to the mass of cementitious materials 32per unit area that the cementitious mixture 30 absorbs during in-situhydration that provides the enhanced post-hydration and post-cureproperties (e.g., a maximum 28-day compressive strength, etc.) ofcementitious composite 10. Such a mass of water per unit area may berepresented by the following expression:M _(w) =x·M _(c)  (9)where M_(w) is the mass of water per unit area and x is a hydrationratio of the mass of water added to the cementitious mixture 30 relativeto the mass of cementitious materials 32 of cementitious mixture 30 perunit area (i.e., a water-to-cement ratio). According to an exemplaryembodiment, x is between a lower hydration ratio threshold of 0.25 andan upper hydration ratio threshold of 0.55. The lower hydration ratiothreshold of 0.25 may correspond with the lower void fraction value(e.g., 0.64, etc.), an intermediate hydration ratio of 0.30 maycorrespond with an intermediate void fraction value (e.g., 0.80, etc.),and the upper hydration ratio threshold of 0.55 may correspond with theupper void fraction value (e.g., 1.35, etc.). The hydration ratiothreshold may vary with the mass of cementitious materials 32 per unitarea and/or the volume of voids 38 per unit area, among othercharacteristics. Applicant has found that if the mass of cementitiousmaterials 32 per unit area is relatively low, a lesser mass of waterneeds to be applied to cementitious composite 10 and that if the mass ofcementitious materials 32 per unit area is relatively large, a greatermass of water needs to be applied to cementitious composite 10. In someembodiments, the lower hydration ratio threshold is greater than 0.25(e.g., 0.28, 0.30, 0.31, 0.32. 0.34, 0.35, 0.36, 0.37, 0.38, 0.39, 0.40,0.41, 0.42, 0.43, 0.44, 0.45, etc.) or less than 0.25 (e.g., 0.10, 0.12,0.15, 0.18, 0.20, 0.22, etc.). In some embodiments, the upper hydrationratio threshold is greater than 0.55 (e.g., 5, 0.56, 0.57, 0.58, 0.59,0.60, 0.61, 0.62, 0.63, 0.64, 0.65, etc.) or less than 0.55 (e.g., 0.54,0.53, 0.52, 0.51, 0.50, 0.49, 0.48, 0.47, 0.46, etc.).

According to another embodiment, cementitious composite 10 having acementitious mixture 30 that at least one of (i) includes colloidalcement, (ii) is compacted in a specific arrangement, and (iii) undergoesa specific treatment process to provide particles of varying size and/orshape requires a hydration ratio between 0.15 and 3.5 to provide theenhanced post-hydration and post-cure properties (e.g., a maximum 28-daycompressive strength, etc.) of cementitious composite 10. In someembodiments, cementitious mixture 30 includes a viscosifier or arelatively higher dose of a viscosity modifier at higher hydrationratios (e.g., higher than 0.55, etc.).

As utilized herein, the terms “approximately,” “about,” “substantially,”and similar terms are intended to have a broad meaning in harmony withthe common and accepted usage by those of ordinary skill in the art towhich the subject matter of this disclosure pertains. It should beunderstood by those of skill in the art who review this disclosure thatthese terms are intended to allow a description of certain featuresdescribed without restricting the scope of these features to the precisenumerical ranges provided. Accordingly, these terms should beinterpreted as indicating that insubstantial or inconsequentialmodifications or alterations of the subject matter described areconsidered to be within the scope of the invention.

It should be noted that the term “exemplary” as used herein to describevarious embodiments is intended to indicate that such embodiments arepossible examples, representations, and/or illustrations of possibleembodiments (and such term is not intended to connote that suchembodiments are necessarily extraordinary or superlative examples).

The terms “coupled,” “connected,” and the like as used herein mean thejoining of two members directly or indirectly to one another. Suchjoining may be stationary (e.g., permanent) or movable (e.g., removableor releasable). Such joining may be achieved with the two members or thetwo members and any additional intermediate members being integrallyformed as a single unitary body with one another or with the two membersor the two members and any additional intermediate members beingattached to one another.

Also, the term “or” is used in its inclusive sense (and not in itsexclusive sense) so that when used, for example, to connect a list ofelements, the term “or” means one, some, or all of the elements in thelist. Conjunctive language such as the phrase “at least one of X, Y, andZ,” unless specifically stated otherwise, is otherwise understood withthe context as used in general to convey that an item, term, etc. may beeither X, Y, Z, X and Y, X and Z, Y and Z, or X, Y, and Z (i.e., anycombination of X, Y, and Z). Thus, such conjunctive language is notgenerally intended to imply that certain embodiments require at leastone of X, at least one of Y, and at least one of Z to each be present,unless otherwise indicated.

It should be noted that the orientation of various elements may differaccording to other exemplary embodiments and that such variations areintended to be encompassed by the present disclosure.

It is important to note that the construction and arrangement of theelements of the systems and methods as shown in the exemplaryembodiments are illustrative only. Although only a few embodiments ofthe present disclosure have been described in detail, those skilled inthe art who review this disclosure will readily appreciate that manymodifications are possible (e.g., variations in sizes, dimensions,structures, shapes and proportions of the various elements, values ofparameters, mounting arrangements, use of materials, colors,orientations, etc.) without materially departing from the novelteachings and advantages of the subject matter recited. For example,elements shown as integrally formed may be constructed of multiple partsor elements. It should be noted that the elements and/or assemblies ofthe enclosure may be constructed from any of a wide variety of materialsthat provide sufficient strength or durability, in any of a wide varietyof colors, textures, and combinations. Additionally, in the subjectdescription, the word “exemplary” may be used to mean serving as anexample, instance or illustration. Any embodiment or design describedherein as “exemplary” may be not necessarily to be construed aspreferred or advantageous over other embodiments or designs. Rather, useof the word exemplary may be intended to present concepts in a concretemanner. Accordingly, all such modifications are intended to be includedwithin the scope of the present inventions. The order or sequence of anyprocess or method steps may be varied or re-sequenced according toalternative embodiments. Any means-plus-function clause may be intendedto cover the structures described herein as performing the recitedfunction and not only structural equivalents but also equivalentstructures. Other substitutions, modifications, changes, and omissionsmay be made in the design, operating conditions, and arrangement of thepreferred and other exemplary embodiments without departing from scopeof the present disclosure.

The invention claimed is:
 1. A cementitious composite for in-situhydration, comprising: a first layer; a second layer spaced from thefirst layer; a cementitious mixture disposed between the first layer andthe second layer, the cementitious mixture including cementitiousmaterials shaped and arranged to provide a void fraction of between 0.64and 1.35, wherein the void fraction is defined as the ratio of thevolume of the voids within the cementitious mixture per unit area of thecementitious composite to the volume of the cementitious materials perunit area of the cementitious composite; and a structure layercomprising a nonwoven material and disposed between the first layer andthe second layer, wherein the cementitious mixture is disposed withinthe structure layer; wherein the cementitious mixture is configured toabsorb a mass of water that provides a maximum 28 day compressivestrength of the cementitious composite; and wherein:M _(w) =x·M _(c) where: M_(w) is the mass of the water per unit area ofthe cementitious composite; M_(c) is a mass of the cementitiousmaterials of the cementitious mixture per unit area of the cementitiouscomposite; and x is a ratio of the mass of the water relative to themass of the cementitious materials of the cementitious mixture per unitarea of the cementitious composite that provides the maximum 28 daycompressive strength of the cementitious composite, wherein x is between0.25 and 0.55.
 2. The cementitious composite of claim 1, wherein theratio of the mass of the water relative to the mass of the cementitiousmaterials of the cementitious mixture that provides the maximum 28 daycompressive strength of the cementitious composite is between 0.30 and0.55.
 3. The cementitious composite of claim 1, wherein the first layeris a sealing layer positioned to seal a first side of the cementitiouscomposite such that the cementitious mixture and water does not migratethrough the first side.
 4. The cementitious composite of claim 1,wherein the second layer is a containment layer positioned at anopposite second side of the cementitious composite to at least partiallycontain the cementitious mixture within the cementitious composite. 5.The cementitious composite of claim 4, wherein the containment layer iswater permeable and thereby configured to facilitate the in-situhydration of the cementitious mixture.
 6. A method for manufacturing acementitious composite for in-situ hydration, the method comprising:providing a first layer; providing a second layer; providing a structurelayer comprising a nonwoven material and disposed between the firstlayer and the second layer; and disposing a cementitious mixture betweenthe first layer and the second layer, wherein the cementitious mixtureis disposed within the structure layer, the cementitious mixtureincluding cementitious materials shaped and arranged to provide a voidfraction of between 0.64 and 1.35, wherein the void fraction is definedas the ratio of the volume of the voids within the cementitious mixtureper unit area of the cementitious composite to the volume of thecementitious materials per unit area of the cementitious composite;wherein the cementitious mixture is configured to absorb a mass ofwater, and the first layer and the second layer are configured tofacilitate the absorption of the mass of water by the cementitiousmixture, that provides a maximum 28 day compressive strength of thecementitious composite upon curing, wherein a ratio of the mass of thewater relative to a mass of the cementitious materials of thecementitious mixture that provides the maximum 28 day compressivestrength is between 0.25 and 0.55.
 7. The method of claim 6, wherein theratio of the mass of the water relative to the mass of the cementitiousmaterials of the cementitious mixture that provides the maximum 28 daycompressive strength of the cementitious composite is between 0.30 and0.55.
 8. The method of claim 6, wherein the first layer is a sealinglayer positioned to seal a first side of the cementitious composite suchthat the cementitious mixture and water does not migrate through thefirst side.
 9. The method of claim 6, wherein the second layer is acontainment layer positioned at an opposite second side of thecementitious composite to at least partially contain the cementitiousmixture within the cementitious composite.
 10. The method of claim 9,wherein the containment layer is water permeable and thereby configuredto facilitate the in-situ hydration of the cementitious mixture.
 11. Themethod of claim 6, further comprising a disposing a structure layerbetween the first layer and the second layer, wherein the cementitiousmixture is disposed within the structure layer, and wherein thestructure layer is configured to facilitate the absorption of the massof water by the cementitious mixture that provides a maximum 28 daycompressive strength of the cementitious composite upon curing.
 12. Themethod of claim 6, further comprising compacting the cementitiousmixture between the first layer and the second layer.
 13. Thecementitious composite of claim 1, wherein at least one of (a) the firstlayer, the second layer, and the structure layer are configured tofacilitate the absorption of the mass of water by the cementitiousmixture that provides the maximum 28 day compressive strength of thecementitious composite, (b) the first layer, the second layer, and thestructure layer are configured to permit uninhibited expansion of thecementitious mixture, and (c) the cementitious mixture is of anonexpansive type.
 14. A cementitious composite for in-situ hydration,comprising: a first layer; a second layer spaced from the first layer;and a cementitious mixture disposed between the first layer and thesecond layer, the cementitious mixture including cementitious materialsand super absorbent polymers, the cementitious materials shaped andarranged to provide a void fraction of between 0.30 and 1.35, whereinthe void fraction is defined as the ratio of the volume of the voidswithin the cementitious mixture per unit area of the cementitiouscomposite to the volume of the cementitious materials per unit area ofthe cementitious composite; wherein the cementitious mixture isconfigured to absorb a mass of water that provides a maximum 28 daycompressive strength of the cementitious composite; and wherein:M _(w) =x·M _(c) where: M_(w) is the mass of the water per unit area ofthe cementitious composite; M_(c) is a mass of the cementitiousmaterials of the cementitious mixture per unit area of the cementitiouscomposite; and x is a ratio of the mass of the water relative to themass of the cementitious materials of the cementitious mixture per unitarea of the cementitious composite that provides the maximum 28 daycompressive strength of the cementitious composite, wherein x is between0.25 and 0.55.